Conventionally, in a field of the vehicle controller, an X-by-wire system is well known, in which an actuator is controlled with a by-wire circuit under control of a driver's instruction for adjusting and changing a vehicle state, and, among which a shift-by-wire system is a representative one. For example, a Japanese patent document 1, i.e., JP 2004-129452 A, discloses a shift-by-wire system in which a phase advance amount of a power supply phase relative to a rotation phase of a rotor is set for a motor control according to a rotation speed of the rotor.
(Patent document 1) Japanese Patent Laid-Open No. 2004-129452
In the shift-by-wire system for switching the shift position with a by-wire system, the shift position is more quickly switched than a manual shift switching operation of the driver, for example. However, as a trade-off, at a time of releasing a lock state of a lock mechanism, which is caused by the switching of the shift position into the parking position, the shift-by-wire system may generate a large noise. In the above-described patent document 1, no consideration is provided for preventing such a noise at a lock release time.